Fix xrootd_sec_level puppet data type
xrootd_sec_level puppet variable is optional array of strings, because we can have different configuration for local vs. remote https://xrootd.slac.stanford.edu/doc/dev49/sec_config.htm#_Toc517294094
xrootd_sec_level puppet variable is optional array of strings, because we can have different configuration for local vs. remote https://xrootd.slac.stanford.edu/doc/dev49/sec_config.htm#_Toc517294094